Dial-adjusting mechanism for radio apparatus



we, RNEY July 13 1926.

T. R. MOORE DIAL ADJUSTING MECHANISM FOR RADIO APPARATUS Patented July 13, 1926.

- UNITED, STATES PATENT OFFICE.

THOMAS R. MOORE, OF WARWICK, NEW YORK.

DIAL-ADJUSTING MECHANISM FOR RADIO APPARATUS.

Application filed May 9, 1925. Serial No. 29,118.

The invention relates to dial mechanisms for radid apparatus, and one object of the invention is to equip anindexed dial for radio work having an indicating needle or pointer adapted to be rapidlymoved to approxi-.'

mately the desired position on the dial, with means, whereby then the needle or pointer may be accurately and positively finely adjusted to its final position; The needle or pointer is provided with a knob for its manual rapid or coarse adjustment and with a worm mechanism for its final fine or micrometer adjustment, said worm mechanism preferably being pivotally mounted so as to be swung away from or into engagement with a.

toothed se ment formed on the hub portion of the needle or pointer, and said mechanism comprising a spring adapted to lock said worm mechanism in its position free of said toothed segment and also in its position of engagement with said toothed segment, the relation of the s ring to the worm mechanism preferably eing such that the spring acts to urge the worm against the segment instead of having a dead locking engagement against the worm mechanism, and the purpose of this feature being to secure an ac curate engagement of the worm with the segment even though the teeth on the segment or possibly the thread on the worm may become worn in use or some irregularity in manufacture or assembly take place.

I present my invention herein, by way of illustration, as associated with atuning dial and a'ariable condenser of a radio receiving apparatus. but my invention is not confined to use with condensers, since it is also applicable for use with, variometers, vanecouplers and the like of radio, ap aratus. The invention will be fully unc erstood from the detailed description hereinafter presented of a referred embodiment thereof, reference being bad to the accompanying drawings, in which:

Fig. 1 is a front elevation of a portion of a radio receiving ap aratus and illustrates a tuning dial, its nee leor pointer and the adjusting mechanism of my invention shown in operative position with the worm in engagement with the toothed segment on the hub portion of the needle or pointer and under the spring tension urging the worm into such enga ement; j s Fig. 2 is a similar view of the same but illustratin the worm adjusting mechanism as having heen turned or swung into inoperative position free of the toothed segment on the needle or ointer and releasably locked in such position by the spring which in Fig. 1 is shown as maintaining the worm mechanism in operative position;

Fig. 3 is a horizontal section, on a larger scale, throu h the same taken on the dotted lined-3 0 Fig. 1, and

Fig. 4 is a similar section, on an enlar ed scale, through a portion of the same ta em on the dotted line 4--4 of Fig. 1.

The mechanism of my invention, as illustrated in the drawings, comprises a dial proper, in this instance a tuning-dial, or plate:5 provided on the upper section of its perimeter with the graduations 6. The dial plate 5 is secured by the screws 7 to the front wall 8 of the usual box or casing for containing the radio apparatus. On the front of the circular dial plate 5 is pivotally mounted an indicating needle'or pointer 9. The needle 9 is secured to the frowardly projecting end of a shaft 10 of a variable condenser 12 of usual construction, mounted on the rear of the wall 8 by means of the screws 13.

In order that the indicating needle or pointer 9 may be rapidly moved to approximately the required position. it is provided with the usual knob or handle 14 composed of hard rubber or the like mounted on the forward extremity of the shaft 10. The mounting of the'needle 9 and knob 14 on. the 'forward end of the shaft 10 is clearly indicated in Fig. 3. with a central bore 15 for the accommodation of a bushing 16 which fits snugly on the forward end of the shaft 10 and is secured they-etc by means of the screw 17 The hub portion 18 of the needle 9 is mounted by means of a tight fit on the bushing 16.

The knob is provided It will be observed from an examination of Fig. 3 that the hub 18 of the needle is spaced.

apart from the front face" of the dial 5. This rovides clearance for adjustneedle 9, as shown in Fig. 1. The worm is mounted on the inner end of a shaft 22 journaled in the upturned side walls 24 and 25 of a plate 26 pivotally mounted on the dial plate 5 by means of the screw 27. The plate 26 is frictionally held against the dial 5 by means of the dish-like spring 28. On the outer end of the shaft 22 is secured a knurled knob or handle 30 of hard rubber or like material.

When the screw 20 is in engagement with the teeth of the segmental ear 21 of the ointer 9 it is yieldingly he d thereagainst y means of a pair of spring arms 31 and 32 which are arranged in the form of a V secured at its apex 33 to the plate 5 by means of the screw 34:.- The free ends of the arms 31 and 32 are inturned, the extremity of the arm 31 being provided with the flat face 36, and. the inner face of the inturned end of the arm 32 being flattened at 37. The face 36 of the arm 31 isjr adapted to engage and press against the side wall 38 of a notch 39 cut in the upper side of the hub 40 of the plate 26, and the face 37 of the arm 32 is adapted to engage the side wall 42 of a notch 43 cut in the lower side of the hub 40. By means of this arrangement, the spring arms 31 and 32 tend to press the worm 20 into engagement with the teeth of the segment 21 to compensate for any wear or lost motion. Thus the pointer 9 and the condenser, variometer, variocoupler or other part with which the pointer is connected may be positively and therefore accurately adjusted to the desired final position.

In approximating the desired position of the pointer 9 and so of the condenser by means of the knob 14, the worm 20 is first disconnected from the teeth of the segment 21. This is done by turning the plate or bracket 26, bymeans of the knob 30, to carry the worm in a. direction from the segment. The plate 26 is held in its inoperative position, shown in Fig. 2, with the worm disconnected from the segment 21 by means of the engagement of the inturne ends of the spring arms 31 and 32 with the notches 45 and 46, respectively, cut in the upper and lower sides of the hub section 40 of the plate 26. The engagement of the inturned ends of the spring arms 31 and 32 with the notches 45 and 46 is sufficient to prevent accidental movement of the plate 26 but readily permits the operative to snap the worm into engagement with the segment 21 as soon as the pointer or needle 9 has, by means of the knob or handle 14, been quickly or coarsely turned to approximately the desired position, whereupon the worm 20 will be restored to en agement with the segment 21 (Fig. 1) and made 'use of in turning the needle or pointer 9 carefully to its final position of fine adjustment.

I call attention to the fact that the surfaces 36, 37 of the spring arms 31, 32 are inclined and that the inturned ends of said arms do not bottom in the notches or recesses 39, 43 of the hub of the worm supporting plate or bracket 26 but that the inclined surfaces 36, 37 remain, in the operative position of the worm, against the correspondingly inclined surfaces 38, 42 of the notches or recesses 39, 43,'this construction enabling the surfaces 36, 37 to coact with the surfaces 38, 42 under the tension of the spring arms 31, 32, in maintaining the worm 20 in engagement with the segment 21 by an action of cam nature constantly urging the worm against the segment regardless of ordinary wear of the engaging parts or small defects in the manufacture or assembly of the several parts of the mechanism.

What I claim as my invention and desire to secure by Letters-Patent, is:

1. Mechanism of the character described comprising an indexed dial plate, a pivotally mounted needle or pointer therefor having means for its rapid or coarse adjustment, a toothed segment connected with said needle or pointer, a worm gear movable into and from engagement with said segment for imparting to said needle or pointer its final fine adjustment, said worm gear comprising a pivotally mounted bracket plate and a shaft mounted therein having a worm on one part and a handle on another part, and said bracket plate having oppositely disposed notches, and spring arms adapted to have sliding engagement with walls of said notches for yieldingly urging said worm in-- to engagement with said segment.

2. Mechanism of the character described comprising an indexed dial plate, a pivotally mounted needle or pointer therefor having means for its rapid or coarse adjustment 8. toothed segment connected with said needle or pointer, a Worm gear movable into and from engagement with said segment for imparting to said needle or pointer its final fine adjustment, said worm gear comprising a pivotally mounted bracket plate and a. shaft mounted therein having a worm on one part and a handle on another part, and said bracket plate having two sets of oppositely disposed notches, and a V-shaped spring the arms of which are adapted to engage two opposite notches to yieldingly hold the Worm against said segment and the other posite notches to latch from said segment.

In testimony whereof I hereunto aflix'my signature.

the worm disengaged THOMAS R. MOORE.

two op- 

